The invention relates generally to improvements in an evaporation-cooled internal combustion engine, in which a cooling system, through which a coolant can flow, and to which pressure can be applied, is connected with an equalization container. The equalization container is connected to a steam-filled zone of the cooling system by means of a connection line.
The general type of such an internal combustion engine is known from U.S. Pat. No. 4,648,356. According to this reference, the cooling system generally consists of an engine water mantle, a condenser, a condensate tank, and a container. The container is divided into two chambers by a membrane, where the chamber facing away from the cooling system is open towards the atmosphere. As the temperature of the coolant rises, and as the pressure on the side of the membrane facing towards the cooling system to which it is connected increases, the volume of the cooling system is automatically changed. This system temporarily draws air located within the hermetically sealed system out of the system away from the condenser, and so enhances the functioning of the system. The air, which is disadvantageous for the functioning of the system, is stored in the container having the membrane during operation of the internal combustion engine. Once the engine is stopped and has cooled, the air is passed back into the system in order to avoid the creation of a vacuum. Another component of the system is an electrically driven fan, which allows cooling air to flow past the condenser as needed, and thus changes the temperature of the coolant fluid as a function of the flow of cooling air.
In this known device, little external influence can be exerted on the pressure in the cooling system from the outside. Essentially, the spring characteristic and the atmospheric pressure determine the interior pressure within the cooling system and thus the boiling temperature of the coolant connected with it. The operation of the fan (the only component which can be controlled from the outside) results in only a slight and slow change of the temperature of the coolant. To achieve even this slight effect, however, the fan requires a relatively high amount of energy. Because the pressure in the cooling system is not adjustable to a sufficient degree, it is not always possible to properly adjust the boiling temperature of the coolant in response to the operating condition of the internal combustion engine. Due to this limitation, the temperature of the coolant, as well as the temperature of the parts that are in contact with the combustion space, can not be adjusted to an optimum value for an advantageous course of combustion.
The invention is directed to the problem of further developing an internal combustion engine in which the boiling temperature of the coolant can simply and reliably be controlled over a greater range.